Published online by Cambridge University Press: 05 June 2009
Several important errors and misinterpretations present in a recent publication by Khan et al. [Eur. Phys. J. Appl. Phys. 45, 11002 (2009)] are pointed out and discussed. In particular, it is shown that the method used to calculate the rate coefficients for the electron impact excitation of 3p 54p and 3p 55p states of argon is incorrect and leads to unrealistically high rate coefficients.